Going down the wrong path for human skin?
I was recently dealing with a similar problem.  I found that I didn't really have to worry about it-- these kind of detail, high-res normal maps can stand a bit of noise.  Specular rarely aligns closely enough with a seam for it to be visible.

If you try that and find you're having visible problems, you may want to consider masking your normal map with another (hand-made) texture.  I'm not sure of your application, but with what I was doing, scaling the R and G components down smoothly eliminates the normal map (leaving only the meaningless depth component of the vector).  You may want to consider an unorthodox seaming strategy for this, seaming along the smoothest parts of your model rather than natural lines, since these seam lines are exactly where you'll be masking the normal map.  That may mean using an extra set of UV coordinates.